GASTROPODS

▸ Class Gastropoda ▸ Univalve or having a lost or reduced valve

CHAPTER 12 MOLLUSCS

GASTROPODS GASTROPODS

▸ Torsion ▸ Coiling ▸ Puts gills and mantle cavity up front (no sediment) ▸ Planospiral ▸ Allows foot to be pulled in last as protection ▸ Conispiral ▸ results in self fouling... ▸ dextral vs. sinistral

anus

anterior mantle cavity anus posterior mantle head head cavity mouth mouth

foot GASTROPODS GASTROPODS

▸ Coiling ▸ Mode of Nutrition—varied ▸ Planospiral ovotestis ▸ Mostly rasping with radula

▸ Conispiral eye ▸ Some predaceous— (Conus spp.) ▸ dextral vs. sinistral

lung

digestive tract kidney

GASTROPODS

▸ Internal structure/function ▸ Respiration SLIME! ▸ Air brought in through a pneumostome in pulmonates ▸ Reproduction GASTROPODS GASTROPODS

▸ Classification—subclasses ▸ Pulmonata NUDIBRANCHS ▸ polyphyletic ▸ Prosobranchia ▸ Opisthobranchia GILLS CERATA

RHINOPHORES

TUBERCLES

CEPHALOPODS CEPHALOPODS

▸ Class Cephalopoda— ▸ Squid ▸ Reduced or lost shell in most ▸ some huge! ▸ Chambered Nautilus ▸ (Architeuthis dux, (Nautilus)? Mesonychoteuthis ▸ Cuttlefish hamiltoni) ▸ cuttlebone ▸ often exaggerated ▸ chambers connected by a siphuncle ▸ Reduced to a pen in squid GIANT SQUID VS. CEPHALOPODS SPERM WHALE ▸ Giant squid have been found all over the world

LEGENDARY INVERTEBRATE

CEPHALOPODS CEPHALOPODS

▸ locomotion INTERNAL ANATOMY ▸ Siphon used for jet propulsion (derived from foot) ▸ respiration ▸ pair of ctenidia ▸ Closed circulatory system with multiple hearts ▸ Systemic heart ▸ Branchial or accessory hearts CEPHALOPODS CEPHALOPODS

▸ feeding ▸ Reproduction— ▸ Predaceous ▸ dioecious ▸ Chitinous beak ▸ direct development ▸ blue-ringed octopus (tetrodotoxin) ▸ intromittent structure in males

▸ Sensory ▸ intelligence? ▸ statocysts ▸ hair cells ▸ balance, posture, eye movements, ▸ color matching ▸ visual

CEPHALOPODS CEPHALOPODS

▸ sepia (ink) ▸ Excellent, image-forming eyes (analogous to vertebrate eye) COLOR CHANGE ▸ Chromatophores ▸ color vision? ▸ chromatophores ▸ photocytes CEPHALOPODS CEPHALOPODS COLOR CHANGE COLOR CHANGE

▸ color vision? ▸ color vision? ▸ chromatophores ▸ chromatophores ▸ photocytes ▸ photocytes

CEPHALOPODS platyhelminthes (outgroup) ▸ Subclasses Nautiloidea, Ammonoidea (extinct) and Coleoidea (all living cephalopods except Nautilus) caudofoveata ▸ orders - sepiida (cuttlefish), teuthida, octopoda, vampyromorphida solenogastres

mollusca polyplacophora

monoplacophora

conchifera gastropoda

cephalopoda

bivalvia

Vampyroteuthis infernalis ammonite not a nautilus scaphopoda